Startups University offers a good overview of small business funding, from introducing what options are available to how to find investors based on your needs and situation.
External sources
Business loans – can be obtained from traditional lenders such as banks or credit unions.
Equity financing - funding given in exchange for partial ownership and future profits, debt financing – the money must be repaid.
Grants are also an option and the money does not have to be repaid.
Personal funds
Some entrepreneurs use their own funds or gifts from friends and family to get their small business off the ground.